On Friday, a rocket owned by Elon Musk's company SpaceX exploded in mid-air. It happened during a test flight in Texas, and it was one of those rockets that can take off and then land again. 

According to the company, it blew up because the on-board computer detected some sort of problem, and hit the self-destruct button so it wouldn't fly off course and hit a neighborhood or something. The rockets are unmanned, so no one was hurt.